Providing simultaneous digital and analog services and optical fiber-based distributed antenna systems, and related components and methods

ABSTRACT

Embodiments relate to providing simultaneous digital and analog services in optical fiber-based distributed radio frequency (RF) antenna systems (DASs), and related components and methods. A multiplex switch unit associated with a head-end unit of a DAS can be configured to receive a plurality of analog and digital downlink signals from one or more sources, such as a service matrix unit, and to assign each downlink signal to be transmitted to one or more remote units of the DAS. In one example, when two or more downlink signals are assigned to be transmitted to the same remote unit, a wave division multiplexer/demultiplexer associated with the multiplex switch unit can be configured to wave division multiplex the component downlink signals into a combined downlink signal for remote side transmission and to demultiplex received combined uplink signals into their component uplink signals for head-end side transmission.

PRIORITY APPLICATION

This application is a continuation of International Application No.PCT/US14/17660, filed on Feb. 21, 2014, which claims the benefit ofpriority to U.S. Provisional Application No. 61/769,820, filed on Feb.27, 2013, both applications being incorporated herein by reference.

BACKGROUND

Field of the Disclosure

The technology of the disclosure relates to optical fiber-baseddistributed antenna systems (DASs) for distributing radio frequencies(RFs) and other signals over optical fibers.

Technical Background

Wireless communications are rapidly growing, with ever-increasingdemands for high-speed mobile data communications. As an example,so-called “wireless fidelity,” or “WiFi” systems and wireless local areanetworks (WLANs), are being deployed in many different areas.Distributed antenna systems (DASs) communicate with wireless devicescalled “clients,” which must reside within a wireless range or “cellcoverage area” of the DAS in order to communicate with an access pointdevice. DASs can include analog and digital communications protocols andsignals.

One approach to deploying a DAS involves the use of radio frequency (RF)antenna coverage areas. Antenna coverage areas can have a radius in arange from a few meters up to twenty meters, as an example. Combining anumber of access point devices creates an array of antenna coverageareas. Because the antenna coverage areas each cover small areas, thereare typically only a few users (clients) per antenna coverage area. Thisallows for minimizing the amount of RF bandwidth shared among the usersof a wireless system. It may be desirable to provide antenna coverageareas in a building or other facility to provide DAS access to clientswithin the building or facility. However, it may be desirable to employoptical fibers to distribute communications signals. Benefits ofemploying optical fibers include increased bandwidth.

One type of DAS, called “Radio-over-Fiber” or “RoF,” utilizes RF signalssent over optical fibers to create antenna coverage areas. Such systemscan include a head-end unit (HEU) optically coupled to a plurality ofremote units (RUs) that each provide antenna coverage areas. Theplurality of RUs can each include RF transceivers coupled to an antennato transmit RF signals wirelessly, wherein the plurality of RUs arecoupled to the HEU via optical fiber links. The RF transceivers in theplurality of RUs are transparent to the RF signals. The plurality of RUsconvert incoming optical RF signals from an optical fiber downlink toelectrical RF signals via optical-to-electrical (O/E) converters, whichare then passed to the RF transceivers. The RF transceivers convert theelectrical RF signals to electromagnetic signals via antennas coupled tothe RF transceivers provided in the plurality of RUs. The antennas alsoreceive electromagnetic signals (i.e., electromagnetic radiation) fromclients in the antenna coverage area and convert them to electrical RFsignals (i.e., electrical RF signals in wire). The plurality of RUs thenconvert the electrical RF signals to optical RF signals viaelectrical-to-optical (E/O) converters. The optical RF signals are thensent over an optical fiber uplink to the HEU.

Design, installation, and subsequent modification of DASs presentsignificant challenges, including limited expansion and scalingcapabilities, and limitations regarding compatible technology protocols.These problems are exacerbated when a DAS is intended to provide bothanalog and digital communications and data signals across the system.For example, many conventional solutions require providing multipleoptical and electrical cable connections between a HEU and each RU of aDAS. Thus, expanding bandwidth and a number of channels between the HEUand RUs can require extensive redesign and routing of additional opticaland electrical cables throughout the system. Accordingly, a DAS andrelated components that permit scalability and compatibility with a widearray of different technologies, without extensive reconfiguration ofthe entire system, may be desirable.

SUMMARY OF THE DETAILED DESCRIPTION

Embodiments related to providing simultaneous digital and analogservices in optical fiber-based distributed antenna systems (DASs), andrelated components and methods are disclosed. A multiplex switch unitassociated with a head-end unit of a DAS can be configured to receive aplurality of analog and digital signals from one or more sources, suchas a service matrix unit. The multiplex switch unit can be furtherconfigured to assign each signal to be transmitted to one or more remoteunits of the DAS. In one example, when two or more signals are assignedto be transmitted to the same remote unit, a wave divisionmultiplexer/demultiplexer associated with the multiplex switch unit canwave division multiplex component downlink signals into a combineddownlink signal for remote side transmission, and to demultiplexreceived combined uplink signals into their component uplink signals forhead-end side transmission. Likewise, each remote unit may also includea wave division multiplexer/demultiplexer to separate a receivedcombined downlink signal into individual component downlink signals, andto send received component uplink signals back to the head-end unit asone or more combined uplink signals. In this manner, existing opticalfiber networks can be utilized for carrying both analog and digitalcommunications on common optical fibers, and the amount and types ofservices provided at each remote unit can be individually configured,expanded, or modified to meet demand over time.

In this regard, in one embodiment, a multiplex switch unit for a DAScomprises a plurality of head-end side inputs configured to receive aplurality of component downlink signals comprising at least one downlinkradio frequency (RF) communication signal and at least one downlinkdigital data (DD) signal. The multiplex switch unit also comprises aplurality of remote side optical outputs each configured to transmit atleast one optical downlink signal. The multiplex switch unit alsocomprises a switch connected between the plurality of head-end sideinputs and the plurality of remote side optical outputs. The switch isconfigured to assign each component downlink signal received from theplurality of head-end side inputs to at least one remote side opticaloutput, including assigning at least one downlink RF communicationsignal and at least one downlink DD signal to a common remote sideoptical output. For each remote side optical output, the switch isconfigured to multiplex the respective assigned component downlinksignals into a combined downlink optical signal, and transmit therespective combined downlink optical signal to the respective assignedat least one remote side optical output.

In another exemplary embodiment, a method of operating a multiplexswitch unit for a DAS comprises receiving, at a plurality of head-endside inputs of the multiplex switch unit, a plurality of componentdownlink signals comprising at least one downlink RF communicationsignal and at least one downlink DD signal. The method further comprisesassigning each component downlink signal received at the plurality ofhead-end side inputs to at least one of a plurality of remote sideoptical outputs of the multiplex switch unit, including assigning atleast one downlink RF communication signal and at least one downlink DDsignal to a common remote side optical output. The method alsocomprises, for each remote side optical output, multiplexing therespective assigned component downlink signals into a combined downlinkoptical signal, and transmitting the respective combined downlinkoptical signal to the assigned at least one remote side optical output.

In another exemplary embodiment, a non-transitory computer readablemedium comprises instructions for directing a processor to perform amethod. The method comprises receiving, at a plurality of head-end sideinputs of a multiplex switch unit in a DAS, a plurality of componentdownlink signals comprising at least one downlink RF communicationsignal and at least one downlink DD signal. The method further comprisesassigning each component downlink signal received at the plurality ofhead-end side inputs to at least one of a plurality of remote sideoptical outputs of the multiplex switch unit, including assigning atleast one downlink RF communication signal and at least one downlink DDsignal to a common remote side optical output. The method alsocomprises, for each remote side optical output, multiplexing therespective assigned component downlink signals into a combined opticaldownlink signal, and transmitting the respective combined downlinkoptical signal to the assigned at least one remote side optical output.

In another exemplary embodiment, a DAS comprises a head-end unitincluding a multiplex switch unit and a plurality of remote units. Themultiplex switch unit comprises a plurality of head-end side inputsconfigured to receive a plurality of component downlink signalscomprising at least one downlink RF communication signal and at leastone downlink DD signal. The multiplex switch unit also comprises aplurality of remote side optical outputs each configured to transmit atleast one optical downlink signal to a respective remote unit of theplurality of remote units. The multiplex switch unit further comprises aswitch connected between the plurality of head-end side inputs and theplurality of remote side optical outputs. The switch is configured toassign each component downlink signal received from the plurality ofhead-end side inputs to at least one remote unit, including assigning atleast one downlink RF communication signal and at least one downlink DDsignal to a common remote unit. The switch is further configured to, foreach remote unit, multiplex the respective assigned component downlinksignals into a combined downlink optical signal, and transmit therespective combined downlink optical signal to the respective assignedat least one remote unit.

The foregoing general description and the following detailed descriptionpresent embodiments intended to provide an overview or framework forunderstanding the disclosure. The accompanying drawings are included toprovide a further understanding, and are incorporated into andconstitute a part of this specification. The drawings illustrate variousembodiments, and together with the description serve to explain theprinciples of the concepts disclosed.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic diagram of an exemplary optical fiber-baseddistributed antenna system (DAS);

FIG. 2 is a more detailed schematic diagram of an exemplary head-endunit (HEU) and a remote unit (RU) that can be deployed in the DAS ofFIG. 1;

FIG. 3A is detailed schematic diagram of an exemplary service unit for aHEU that can be deployed in the DAS of FIG. 1 for providing digital dataservices and radio frequency (RF) communication services;

FIG. 3B is a schematic diagram of an exemplary RU that can be deployedin the DAS of FIG. 1 for providing digital data services and RFcommunication services;

FIG. 4 is a partially schematic cut-away diagram of an exemplarybuilding infrastructure in which the DAS in FIG. 1 can be employed;

FIG. 5A is a table representing a configuration for a matrix managementunit;

FIG. 5B is a table representing an alternate configuration for a matrixmanagement unit similar to the configuration table of FIG. 5A;

FIG. 6 illustrates an exemplary workflow for providing simultaneousanalog and digital services over an optical fiber-based DAS according toone embodiment; and

FIG. 7 is a schematic diagram of a generalized representation of acontroller that can be included in any head-end units, remote units,wireless client devices, and/or any other components of a DAS tosimultaneously provide analog and digital services as disclosed herein.

DETAILED DESCRIPTION

Reference will now be made in detail to the embodiments, examples ofwhich are illustrated in the accompanying drawings, in which some, butnot all embodiments are shown. Indeed, the concepts may be embodied inmany different forms and should not be construed as limiting herein;rather, these embodiments are provided so that this disclosure willsatisfy applicable legal requirements. Whenever possible, like referencenumbers will be used to refer to like components or parts.

Embodiments related to providing simultaneous digital and analogservices in optical fiber-based distributed antenna systems (DASs), andrelated components and methods are also disclosed. A multiplex switchunit associated with a head-end unit of a DAS can be configured toreceive a plurality of analog and digital signals from one or moresources, such as a service matrix unit. The multiplex switch unit can befurther configured to assign each signal to be transmitted to one ormore remote units of the DAS. In one non-limiting example, when two ormore signals are assigned to be transmitted to the same remote unit, awave division multiplexer/demultiplexer associated with the multiplexswitch unit can be configured to wave division multiplex componentdownlink signals into a combined downlink signal for remote sidetransmission and to demultiplex received combined uplink signals intotheir component uplink signals for head-end side transmission. Likewise,each remote unit may also include a wave divisionmultiplexer/demultiplexer to separate a received combined downlinksignal into individual component downlink signals, and to send receivedcomponent uplink signals back to the head-end unit as one or morecombined uplink signals. In this manner, existing optical fiber networkscan be utilized for carrying both analog and digital communications oncommon optical fibers, and the amount and types of services provided ateach remote unit can be individually configured, expanded, or modifiedto meet demand over time.

Embodiments disclosed in the detailed description include, but are notlimited to, optical fiber-based DASs that provide and support radiofrequency (RF) communication services and digital data services. The RFcommunication services and digital data services can be distributed overoptical fibers to client devices, such as remote units (RUs) forexample. For example, non-limiting examples of digital data servicesinclude Ethernet, Wireless Local Area Network (WLAN), WorldwideInteroperability for Microwave Access (WiMax), Wireless Fidelity (WiFi),Digital Subscriber Line (DSL), and Long Term Evolution (LTE), etc.Digital data services can be distributed over common optical fibers withRF communication services. For example, digital data services can bedistributed over common optical fibers with RF communication services atdifferent wavelengths through wavelength-division multiplexing (WDM)and/or at different frequencies through frequency-division multiplexing(FDM). Power distributed in the optical fiber-based DAS to provide powerto RUs can also be accessed to provide power to digital data servicecomponents.

FIG. 1 is a schematic diagram of an embodiment of an optical fiber-basedDAS. In this embodiment, the DAS is an optical fiber-based DAS 10 thatis configured to create one or more antenna coverage areas 12 forestablishing communications with wireless client devices located in a RFrange of the antenna coverage areas 12. The optical fiber-based DAS 10also provides RF communications service (e.g., cellular services). Inthis embodiment, the optical fiber-based DAS 10 includes a head-end unit(HEU) 14 and one or more remote units (RUs) 16. The HEU 14 is configuredto receive communications over downlink electrical signals 18D from asource or sources, such as a network or carrier as examples, and providesuch communications to the RU 16 via optical fiber 20 that opticallycouples the HEU 14 to the RU 16. The HEU 14 is also configured to returncommunications received from the RU 16, via uplink electrical signals18U, back to the source or sources. In this regard in this embodiment,the optical fiber 20 includes at least one downlink optical fiber 20D tocarry signals communicated from the HEU 14 to the RU 16, and at leastone uplink optical fiber 20U to carry signals communicated from the RU16 back to the HEU 14.

The DAS 10 has an antenna coverage area 12 that can be substantiallycentered about the RU 16. The antenna coverage area 12 of the RU 16forms an RF coverage area 22. The HEU 14 is adapted to perform or tofacilitate any one of a number of Radio-over-Fiber (RoF) applications,such as RF identification (RFID), wireless local-area network (WLAN)communication, or cellular phone service. Shown within the antennacoverage area 12 is a client device 24 in the exemplary form of a mobiledevice, which may be a cellular telephone as an example. The clientdevice 24 can be any device that is capable of receiving RFcommunication signals. The client device 24 includes an antenna 26(e.g., a wireless card) adapted to receive and/or send electromagneticRF signals.

With continuing reference to FIG. 1, to communicate the electrical RFsignals over the downlink optical fiber 20D to the RU 16, to in turn becommunicated to the client device 24 in the antenna coverage area 12formed by the RU 16, the HEU 14 includes an electrical-to-optical (E/O)converter 28. The E/O converter 28 converts the downlink electricalsignals 181) to downlink optical signals 30D to be communicated over thedownlink optical fiber 20D. The RU 16 includes an optical-to-electrical(O/E) converter 32 to convert received downlink optical signals 30D backto electrical RF signals to be communicated wirelessly through anantenna 34 of the RU 16 to the client device 24 located in the antennacoverage area 12.

Similarly, the antenna 34 is also configured to receive wireless RFcommunications from client devices 24 in the antenna coverage area 12.In this regard, the antenna 34 receives wireless RF communications fromthe client devices 24 and communicates electrical RF signalsrepresenting the wireless RF communications to an E/O converter 36 inthe RU 16. The E/O converter 36 converts the electrical RF signals intouplink optical signals 30U to be communicated over the uplink opticalfiber 20U. An O/E converter 38 provided in the HEU 14 converts theuplink optical signals 30U into uplink electrical RF signals, which canthen be communicated as uplink electrical signals 18U back to a networkor other source. The HEU 14 in this embodiment is not able todistinguish the location of the client devices 24. The client devices 24could be in a range of any antenna coverage area 12 formed by an RU 16.

In the optical fiber-based DAS 10 of FIG. 1 and other DASs, there is aneed to simultaneously provide both analog and digital services todifferent RUs 16. FIG. 2 is a more detailed schematic diagram of the DAS10 of FIG. 1 that provides both RF service and digital data signals. Inan exemplary embodiment, the HEU 14 includes a service unit 40 thatprovides electrical RF service signals by passing (or by conditioningand then passing) such signals from one or more external devices 42 viaa link 44, such as a local device link or network link. In a particularembodiment, these services may include providing WLAN signaldistribution as specified in the Institute of Electrical and ElectronicsEngineers (IEEE) 802.11 standard, i.e., in a frequency range from 2.4 to2.5 GigaHertz (GHz) and from 5.0 to 6.0 GHz. Any other electrical RFsignal frequencies or digital data service formats are also possible.

In another exemplary embodiment, the service unit 40 provides electricalRF service signals or digital data signals by generating the signalsdirectly. In another exemplary embodiment, the service unit 40coordinates the delivery of the electrical service signals between theclient devices 24 within the antenna coverage area 12. These analogand/or digital services may be provided at a head-end side of the HEU14, for example one or more service matrix cards (not shown) thatinterface with a matrix management unit (MMU) 46. The MMU 46 may also beconfigured to interface with one or more external devices 42, such as aconventional base transceiver station (BTS) or a small cell unit(described in detail with respect to FIG. 4). With continuing referenceto FIG. 2, the MMU 46 may be coupled to one or more converter pairs 48,each comprising an E/O converter 28 and an O/E converter 38, within amultiplex switch unit 50. The multiplex switch unit 50 is configured toselectively receive and transmit a plurality of analog and digitalsignals to and from each of a plurality of RUs 16 via the service unit40. The multiplex switch unit 50 may have a plurality of head-end sideinput/output port pairs (not shown) for interfacing with individualservice matrix units 52 (described below with respect to FIG. 3A), orthe external devices 42. The multiplex switch unit 50 may be configuredto selectively provide different analog and digital servicessimultaneously to a plurality of different RUs 16.

With continuing reference to FIG. 2, the service unit 40 includes aplurality of E/O converters 28 that receive the downlink electricalsignals 18D from the service unit 40 and convert them to correspondingdownlink optical signals 30D. One advantage of using optical signals isthat optical fiber has a comparatively large amount of bandwidth and iscapable of carrying optical signals containing a large amount ofinformation over long distances. In an exemplary embodiment, the E/Oconverters 28 include a laser (not shown) suitable for deliveringsufficient dynamic range for the RoF applications described herein, andoptionally include a laser driver/amplifier electrically coupled to thelaser. Examples of suitable lasers for the E/O converters 28 include,but are not limited to, laser diodes, distributed feedback (DFB) lasers,Fabry-Perot (FP) lasers, and vertical cavity surface emitting lasers(VCSELs).

The HEU 14 also includes a plurality of O/E converters 38, which areelectrically coupled to the service unit 40 via the multiplex switchunit 50, for example. The O/E converters 38 receive the uplink opticalsignals 30U and convert them to corresponding uplink electrical signals18U, so that they may be routed to the various external devices 42 bythe local electronic circuitry of the HEU 14. In an exemplaryembodiment, the O/E converter 38 is a photodetector, or a photodetectorelectrically coupled to a linear amplifier. The E/O converter 28 and theO/E converter 38 constitute a “converter pair” 48, as illustrated inFIG. 2.

In accordance with an exemplary embodiment, the multiplex switch unit 50in the service unit 40 of the HEU 14 can include a modulator/demodulatorunit 54, such as a wave division multiplexer/demultiplexer, formultiplexing the downlink RF and DD component signals, anddemultiplexing the uplink combined RF and DD component electricalsignals, respectively. The service unit 40 can include a digital signalprocessing unit (“digital signal processor”) 56 for providing to themodulator/demodulator unit 54 an electrical signal that is modulatedonto an RF carrier (not shown) to generate a desired downlink electricalsignal 18D. The digital signal processor 56 is also configured toprocess a demodulation signal provided by the demodulation of the uplinkelectrical signal 18U by the modulator/demodulator unit 54. The HEU 14can also include an optional central processing unit (CPU) 58 forprocessing data and otherwise performing logic and computing operations,and a memory unit 60 for storing data, such as data to be transmittedover a WLAN or other network for example.

In this manner, when more than one downlink signal is assigned by themultiplex switch unit 50 to be transmitted to the same RU 16, themodulator/demodulator unit 54 can be configured to combine the componentdownlink signals into a combined downlink signal for remote sidetransmission, and to divide received combined uplink signals into theircomponent uplink signals for head-end side transmission to therespective service interface, such as an external device 42. Forexample, the modulator/demodulator unit 54 may include a wave divisionmultiplexer/demultiplexer. In this manner, existing optical fibernetworks can be utilized for providing both analog and digitalcommunications over the same optical fibers 20, and the amount and typesof services provided at each RU 16 can be individually configured,expanded or modified to meet demand over time. In this manner as well,each RU 16 requires a single fiber optic cable pair to run between theRU 16 and the HEU 14 to receive a plurality of both analog and digitalcomponent signals.

With continuing reference to FIG. 2, the RU 16 also includes a converterpair 62 comprising the O/E converter 32 and the E/O converter 36. TheO/E converter 32 converts the received downlink optical signals 30D fromthe HEU 14 back into downlink electrical signals 64D. The E/O converter36 converts uplink electrical signals 64U received from the clientdevice 24 into the uplink optical signals 30U to be communicated to theHEU 14. The O/E converter 32 and the E/O converter 36 are electricallycoupled to the antenna 34 via a signal-directing element 67, such as acirculator. The signal-directing element 67 serves to direct thedownlink electrical signals 64D and the uplink electrical signals 64U,as discussed below. In accordance with an exemplary embodiment, theantenna 34 can include one or more patch antennas, such as disclosed inU.S. patent application Ser. No. 11/504,999, filed Aug. 16, 2006entitled “Radio-over-Fiber Transponder With A Dual-Band Patch AntennaSystem,” and U.S. patent application Ser. No. 11/451,553, filed Jun. 12,2006 entitled “Centralized Optical Fiber-Based Wireless PicocellularSystems and Methods,” both of which are incorporated herein by referencein their entireties.

The DAS 10 also includes a power supply 66 that generates an electricalpower signal 68. The power supply 66 is electrically coupled to the HEU14 for powering the power-consuming elements therein. In an exemplaryembodiment, an electrical power line 70 runs through the HEU 14 and overto the RU 16 to power the O/E converter 32 and the E/O converter 36 inthe converter pair 62, the signal-directing element 67 (unless thesignal-directing element 67 is a passive device, such as a circulatorfor example), and any other power-consuming elements provided. Theelectrical power line 70 includes two wires 72 and 74 that carry asingle voltage and that are electrically coupled to a DC power converter76 at the RU 16. The DC power converter 76 is electrically coupled tothe O/E converter 32 and the E/O converter 36 in the converter pair 62,and changes the voltage or levels of the electrical power signal 68 tothe power level(s) required by the power-consuming components in the RU16. The DC power converter 76 can be either a DC/DC power converter oran AC/DC power converter, depending on the type of the electrical powersignal 68 carried by the electrical power line 70. In anotherembodiment, the electrical power line 70 runs directly from the powersupply 66 to the RU 16, rather than from or through the HEU 14. Inanother exemplary embodiment, the electrical power line 70 includes morethan two wires 72, 74 and carries multiple voltages.

FIG. 3A is a schematic diagram of exemplary internal components in theservice unit 40 of FIG. 2 illustrating a more detailed layout of thecomponents and connections therebetween. This detailed view provides amore focused description of the signal assignment and distributionfunctionality of the service unit 40. The service unit 40, which isconfigured to be installed in the HEU 14, includes the MMU 46, theservice matrix units 52, the multiplex switch unit 50, and themodulator/demodulator unit 54. In this embodiment, a remote side of theMMU 46 is connected to the plurality of head-end sides of the multiplexswitch unit 50 via a plurality of remote side input/output (I/O)connections 78D, 78U. The multiplex switch unit 50 may also haveadditional I/O connections 78D, 78U connected to head-end sideinput/output port pairs 80D, 80U for interfacing with one or moreexternal devices 42 (not shown) as well.

Component downlink signals are received by the multiplex switch unit 50via the remote side output connections 78D of the MMU 46. In thisembodiment, the component downlink signals include at least one downlinkRF communication signal and at least one downlink DD signal. Eachcomponent downlink signal is then assigned to at least one of aplurality of remote side optical outputs 82D of the multiplex switchunit 50. At least one downlink RF communication signal and at least onedownlink DD signal are assigned to a single common remote side opticaloutput 82D. For each remote side optical output 82D having only oneassigned component downlink signal, the respective component downlinksignal is passed through and transmitted as a component downlink opticalsignal to the assigned remote side optical output(s) 82D. For eachremote side optical output 82D having more than one assigned componentdownlink signal, the respective assigned component downlink signals aremultiplexed into a combined downlink optical signal. The combineddownlink optical signal is then transmitted to the assigned remote sideoptical output(s) 82D.

Each remote side optical output 82D has a complementary remote sideoptical input 82U, each configured to receive uplink optical signals 30Ufrom a respective connected RU 16 (not shown). If the received uplinkoptical signal 30U is a combined uplink optical signal, the signal isdemultiplexed into its component uplink optical signals by themodulator/demodulator unit 54 of the multiplex switch unit 50. Themultiplex switch unit 50 then routes each received component uplinksignal toward its respective service matrix unit 52, external device 42,or other service interface.

FIG. 3B is a schematic diagram of internal components in the RU 16 ofFIG. 3A to further illustrate how the downlink and uplink optical fibers20D, 20U, and electrical power line 70 are provided to the RU 16 and canbe distributed therein. The downlink and uplink optical fibers 20D, 20U,which provide optical signal transmission of the multiplexed combineddownlink optical signals 30D received from the HEU 14 and complementarycombined uplink optical signals 30U transmitted back to the HEU 14, comeinto a housing 84 of the RU 16, along with the electrical power line 70.The downlink and uplink optical fibers 20D, 20U are first routed to themodulator/demodulator unit 86, which divides combined downlink signalsinto their component signals. RF communications are routed to the O/Econverter 32 and to the antenna 34, as also illustrated in FIG. 2 and aspreviously discussed. Meanwhile, digital data services are routed fromthe modulator/demodulator unit 86 to a digital data services interface88 provided as part of the RU 16 to provide access to digital dataservices via a port 90, which will be described in more detail below.The electrical power line 70 carries power that is configured to providepower to the converter pair 62 and to the digital data servicesinterface 88. The electrical power line 70 is coupled to a voltagecontroller 91 that regulates and provides the correct voltage to theconverter pair 62 and to the digital data services interface 88 andother circuitry in the RU 16.

The digital data services interface 88 converts downlink optical signals30D into downlink electrical digital signals 92D that can be accessedvia the port 90. The interface 88 also converts uplink electricaldigital signals 92U received through the port 90 into uplink opticalsignals 30U to be provided back to the HEU 14. In this regard, a mediaconverter 94 is provided in the digital data services interface 88 toeffect these conversions. The media converter 94 contains an O/E digitalconverter 96 to convert downlink optical digital signals 981) intodownlink electrical digital signals 92D. The media converter 94 alsocontains an E/O digital converter 100 to convert uplink electricaldigital signals 92U received through the port 90 into uplink opticaldigital signals 98U to be provided back to the modulator/demodulatorunit 86. Power from the electrical power line 70 is provided to thedigital data services interface 88 to provide power to the mediaconverter 94.

In this embodiment, when a RU 16 receives a combined downlink signal,the modulator/demodulator unit 86 divides the combined downlink signalinto its component downlink signals and, based on the interface type foreach component downlink signal, routes each signal to either O/E digitalconverter 96 and E/O digital converter 100 or to the digital dataservices interface 88. Likewise, for each RU 16 that receives more thanone component uplink signal at a RU 16, the component uplink signals aremultiplexed by the modulator/demodulator unit 86 into a combined opticaluplink signal and transmitted over the uplink optical fiber 20U to theHEU 14.

Because electrical power is provided to the RU 16 and the digital dataservices interface 88, this also provides an opportunity to providepower for digital devices connected to the RU 16 via the port 90. Inthis regard, a power interface 102 is also provided in the digital dataservices interface 88, as illustrated in FIG. 3B. The power interface102 is configured to receive power from the electrical power line 70 viathe voltage controller 91, and to also make power accessible through theport 90. In this manner, if a client device 24 (not shown) contains acompatible connector to connect to the port 90, not only will digitaldata services be accessible, but power from the electrical power line 70can also be accessed through the same port 90. Alternatively, the powerinterface 102 could be coupled to a separate port from the port 90 fordigital data services.

Further, the HEU 14 could include low level control and management ofthe media converter 94 using communication supported by the HEU 14. Forexample, the media converter 94 could report functionality data (e.g.,power on, reception of optical digital data, etc.) to the HEU 14 overthe uplink optical fiber 20U that carries communication services. The RU16 can include a microprocessor that communicates with the mediaconverter 94 to receive this data and communicate this data over theuplink optical fiber 20U to the HEU 14.

In this manner, different analog and digital services can be selectivelyprovided to different RUs 16 and client devices 24 throughout differentareas covered by the DAS 10. FIG. 4 provides further illustration of howan optical fiber-based DAS such as shown in FIGS. 1-3B can be deployedindoors. FIG. 4 is a partially schematic cut-away diagram of a buildinginfrastructure 104 employing an optical fiber-based DAS 10′ similar tothe optical fiber-based DAS 10 of FIGS. 1-3B. The buildinginfrastructure 104 generally represents any type of building in whichthe optical fiber-based DAS 10′ can be deployed. As previously discussedwith regard to FIGS. 1 and 2, the optical fiber-based DAS 10′incorporates the HEU 14(1) to provide various types of communicationservices to antenna coverage areas within the building infrastructure104, as an example. For example, as discussed in more detail below, theoptical fiber-based DAS 10′ in this embodiment is configured to receivewireless RF signals and convert the RF signals into RoF signals to becommunicated over the optical fiber 20 to multiple RUs 16. The opticalfiber-based DAS 10′ in this embodiment can be, for example, an indoorDAS (IDAS) to provide wireless service inside the buildinginfrastructure 104. These wireless signals can include cellular service,wireless services such as RFID tracking, WiFi, local area network (LAN),WLAN, and combinations thereof.

With continuing reference to FIG. 4, the building infrastructure 104includes a first (ground) floor 106, a second floor 108, and a thirdfloor 110. The floors 106, 108, 110 are serviced by the HEU 14(1)through a main distribution frame 112 to provide antenna coverage areas114 in the building infrastructure 104. Only the ceilings of the floors106, 108, 110 are shown in FIG. 4 for simplicity of illustration. Inthis embodiment, a main cable 116 has a number of different sectionsthat facilitate the placement of a large number of RUs 16 in thebuilding infrastructure 104. Each RU 16 in turn services its owncoverage area in the antenna coverage areas 114. The main cable 116 caninclude, for example, a riser cable 118 that carries all of the downlinkand uplink optical fibers 20D, 20U to and from the HEU 14(1). The risercable 118 may be routed through an interconnect unit (ICU) (not shown).The main cable 116 can include one or more multi-cable (MC) connectors(not shown) adapted to connect select downlink and uplink optical fibers20D, 20U, along with an electrical power line 70 (not shown), to anumber of optical fiber cables 120. Additional slave HEUs 14(2)-14(4)can be included in the DAS 10′ and connected back to master HEU 14(1).Each slave HEU 14(2)-14(4) is responsible for managing a subset of RUs16 in the DAS 10′.

Each HEU 14 is able to receive additional services as well. In thisembodiment, slave HEU 14(2) is connected to a small cell unit 122, whichprovides a separate suite of analog and/or digital services to the DAS10′ independently of the BTS 124. In addition, small cell units 122 maybe connected to individual RUs 16 to provide services to those specificRUs 16. In this manner, as small cell deployment increases or decreasesfor different services and RUs 16, the multiplex switch unit 50 of eachHEU 14 can activate or deactivate BTS 124 based services as needed. Forexample, if a small cell renders a BTS 124 based service redundant for aportion of the DAS 10′, the multiplex switch unit 50 can be configuredto only send the BTS 124 based service to RUs 16 of the DAS 10′ notalready serviced by the small cell unit 122.

The main cable 116 enables multiple optical fiber cables 120 to bedistributed throughout the building infrastructure 104 (e.g., fixed tothe ceilings or other support surfaces of each floor 106, 108, 110) toprovide the antenna coverage areas 114 for the first, second, and thirdfloors 106, 108, 110. In one embodiment, the HEU 14 is located withinthe building infrastructure 104 (e.g., in a closet or control room),while in another embodiment, the HEU 14 is located outside of thebuilding infrastructure 104 at a remote location. The BTS 124, which maybe provided by a second party such as a cellular service provider, isconnected to the HEU 14, and can be co-located or located remotely fromthe HEU 14. A BTS 124 is any station or source that provides an inputsignal to the HEU 14 and can receive a return signal from the HEU 14. Ina typical cellular system, for example, a plurality of BTSs 124 aredeployed at a plurality of remote locations to provide wirelesstelephone coverage. Each BTS 124 serves a corresponding cell and when amobile station enters the cell, the BTS 124 communicates with the mobilestation. Each BTS 124 can include at least one radio transceiver forenabling communication with one or more subscriber units operatingwithin the associated cell.

The optical fiber-based DASs 10, 10′ in FIGS. 1-4 providespoint-to-point communications between the HEU 14 and the RU 16. Each RU16 communicates with the HEU 14 over a distinct downlink and uplinkoptical fiber pair to provide point-to-point communications. Whenever aRU 16 is installed in the optical fiber-based DAS 10, the RU 16 isconnected to a distinct downlink and uplink optical fiber pair connectedto the HEU 14. The downlink and uplink optical fibers 200, 20U may beprovided in the optical fiber 20. Multiple downlink and uplink opticalfiber pairs can be provided in a fiber optic cable to service multipleRUs 16 from a common fiber optic cable. For example, with reference backto FIG. 4, RUs 16 installed on a given floor 106, 108, 110 may beserviced from the same optical fiber 20. The optical fiber 20 may thushave multiple nodes where distinct downlink and uplink optical fiberpairs can be connected to a given RU 16.

As discussed above in reference to FIG. 4, the building infrastructure104 is able to provide digital data services simultaneous with RFcommunications services to client devices 24 located therein. Wired andwireless devices may be located in the building infrastructure 104 thatare configured to access digital data services. Examples of digital dataservices include, but are not limited to, Ethernet, WLAN, WiMax, WiFi,DSL, and LTE, etc. Ethernet standards could be supported, including butnot limited to 100 Megabits per second (Mbs) (i.e., fast Ethernet) orGigabit (Gb) Ethernet, or ten Gigabit (10G) Ethernet. Examples ofdigital data devices include, but are not limited to, WLAN access points126, femtocells 128, gateways 130, baseband units (BBU) 132, remoteradio heads (RRH) 134, and wired and wireless servers 136. Digital dataservices may also be provided via connected desktop computers, hubs,switches, and other devices.

Embodiments disclosed herein provide optical fiber-based DASs thatsupport both RF communications services and digital data services. TheRF communications services and digital data services can be distributedover optical fibers to client devices such as RUs. Alternatively,digital data services can be distributed over common optical fibers withRF communications services in an optical fiber-based DAS. For example,digital data services can be distributed over common optical fibers withRF communications services at different wavelengths throughwavelength-division multiplexing (WDM) and/or at different frequenciesthrough frequency-division multiplexing (FDM).

In order to selectively provide these different analog and digitalservices simultaneously from a number of different modular servicematrix units 52 to different RUs 16 in the DAS 10, the MMU 46 can beconfigured in a variety of ways. Referring now to FIG. 5A, a table 138representing an exemplary configuration for the MMU 46 is illustrated.In this embodiment, each service matrix unit 52 is configured to supporta plurality of services. Each service has a plurality of attributes,including frequency band (column 140), technology (column 142), provider(column 144), and interface (column 146), as are known in the art.

In this embodiment, service matrix unit 52(1) is configured to supportthree services provided by Provider 1. Likewise, service matrix unit52(2) is configured to support four services provided by Provider 2, andservice matrix unit 52(3) is configured to support two services providedby Provider 3. Finally, service matrix unit 52(4) is configured tosupport one service provided by Provider 4, along with a governmentmaintained LTE service and a local WiFi service. Both service matrixunit 52(2) and 52(4) are configured to provide both digital and analogservices from the same service matrix unit 52.

FIG. 5B illustrates a configuration table 138′ for MMU 46 according toan alternative embodiment. In FIG. 5B, the service matrix units 52 eachprovide a plurality of services sharing a common technology. Forexample, service matrix unit 52(5) includes the three analog and digitalLTE services, service matrix unit 52(6) includes the four CDMA services,service matrix unit 52(7) includes the three analog and digital WCDMAservices, and service matrix unit 52(8) includes the local WiFi service.

FIG. 6 a process by which the multiplex switch unit 50 can selectivelyprovide simultaneous analog and digital services over an opticalfiber-based DAS. In workflow 148, a multiplex switch unit, such as themultiplex switch unit 50 of FIGS. 2-4, of a DAS receives a plurality ofcomponent downlink signals at a plurality of head-end side inputs (block150). The plurality of component downlink signals includes at least onedownlink RF communication signal and at least one downlink DD signal.Next, each component downlink signal is assigned to at least one of aplurality of remote side optical outputs, such as remote side opticaloutputs 82D of multiplex switch unit 50 of FIG. 3A (block 152). Thisassignment function includes assigning at least one downlink RFcommunication signal and at least one downlink DD signal to a commonremote side optical output.

For each remote side optical output, the respective assigned componentdownlink signals are multiplexed, for example, by modulator/demodulatorunit 86 of FIGS. 2-4, into a combined downlink optical signal (block154). Each combined downlink optical signal is then transmitted to therespective assigned remote side optical output(s) (block 156). Thisprocess thus facilitates simultaneous distribution of analog and digitalservices over an optical fiber-based DAS.

The above described devices, systems and methods may also be controlledand performed via a processor based computing device or controller. FIG.7 is a schematic diagram representation illustrating components withadditional detail that could be employed in any of the components ordevices disclosed herein or in the distributed antenna systems describedherein, if adapted to execute instructions from an exemplarycomputer-readable medium to perform any of the functions or processingdescribed herein. For example, these components may be integrated intoor be configured to otherwise instruct the service unit 40 of FIGS. 2-4to carry out one or more of the power management schemes describedabove. For example, the processes described in FIG. 6 above could beprovided as a result of executing instructions from a computer-readablemedium. Such a component or device may include a computer system 158,within which a set of instructions for performing any one or more of thedistribution schemes discussed herein may be executed. The computersystem 158 may be connected (e.g., networked) to other machines in aLAN, an intranet, an extranet, or the Internet. While only a singledevice is illustrated, the term “device” shall also be taken to includeany collection of devices that individually or jointly execute a set (ormultiple sets) of instructions to perform any one or more of themethodologies discussed herein. The computer system 158 may be a circuitor circuits included in an electronic board card, such as, a printedcircuit board (PCB), a server, a personal computer, a desktop computer,a laptop computer, a personal digital assistant (PDA), a computing pad,a mobile device, or any other device, and may represent, for example, aserver or a user's computer.

The exemplary computer system 158 includes a processing device orprocessor 160, a main memory 162 (e.g., read-only memory (ROM), flashmemory, dynamic random access memory (DRAM), such as synchronous DRAM(SDRAM), etc.), and a static memory 164 (e.g., flash memory, staticrandom access memory (SRAM), etc.), which may communicate with eachother via a data bus 166. Alternatively, the processing device 160 maybe connected to the main memory 162 and/or static memory 164 directly orvia some other connectivity means. The processing device 160 may be acontroller, and the main memory 162 or static memory 164 may be any typeof memory.

The processing device 160 represents one or more general-purposeprocessing devices, such as a microprocessor, central processing unit,or the like. More particularly, the processing device 160 may be acomplex instruction set computing (CISC) microprocessor, a reducedinstruction set computing (RISC) microprocessor, a very long instructionword (VLIW) microprocessor, a processor implementing other instructionsets, or other processors implementing a combination of instructionsets. The processing device 160 is configured to execute processinglogic in instructions 168 for performing the operations and stepsdiscussed herein.

The computer system 158 may further include a network interface device170. The computer system 158 also may include an input 172, configuredto receive input and selections to be communicated to the computersystem 158 when executing the instructions 168. The computer system 158also may include an output 174, including but not limited to a display,a video display unit (e.g., a liquid crystal display (LCD) or a cathoderay tube (CRT)), an alphanumeric input device (e.g., a keyboard), and/ora cursor control device (e.g., a mouse).

The computer system 158 may include a data storage device 176 thatincludes instructions 178 stored in a computer-readable medium 180. Theinstructions 178 may also reside, completely or partially, within themain memory 162 and/or within the processing device 160 during executionthereof by the computer system 158, wherein the main memory 162 and theprocessing device 160 also constitute the computer-readable medium 180.The instructions 178 may further be transmitted or received over anetwork 182 via the network interface device 170.

While the computer-readable medium 180 is shown in an exemplaryembodiment to be a single medium, the term “computer-readable medium”includes a single medium or multiple media (e.g., a centralized ordistributed database, and/or associated caches and servers) that storethe instructions 168. The term “computer-readable medium” shall alsoinclude any medium that is capable of storing, encoding, or carrying aset of instructions for execution by the processing device and thatcause the processing device to perform any one or more of themethodologies of this disclosure. The term “computer-readable medium”shall accordingly include, but not be limited to, solid-state memories,optical and magnetic medium, and carrier wave signals.

The embodiments disclosed herein include various steps. The steps of theembodiments disclosed herein may be formed by hardware components or maybe embodied in machine-executable instructions, which may be used tocause a general-purpose or special-purpose processor programmed with theinstructions to perform the steps. Alternatively, the steps may beperformed by a combination of hardware and software.

The embodiments disclosed herein may be provided as a computer programproduct, or software, that may include a machine-readable medium (orcomputer-readable medium) having stored thereon instructions, which maybe used to program a computer system (or other electronic devices) toperform processes. A machine-readable medium includes any mechanism forstoring or transmitting information in a form readable by a machine(e.g., a computer). For example, a machine-readable medium includes: amachine-readable storage medium (e.g., ROM, random access memory(“RAM”), a magnetic disk storage medium, an optical storage medium,flash memory devices, etc.); a machine-readable transmission medium(electrical, optical, acoustical, or other form of propagated signals(e.g., carrier waves, infrared signals, digital signals, etc.)); and thelike.

Unless specifically stated otherwise and as apparent from the previousdiscussion, it is appreciated that throughout the description,discussions utilizing terms such as “processing,” “computing,”“determining,” “displaying,” or the like, refer to the action andprocesses of a computer system, or similar electronic computing device,that manipulates and transforms data and memories represented asphysical (electronic) quantities within the computer system's registersinto other data similarly represented as physical quantities within thecomputer system memories or registers or other such information storage,transmission, or display devices. The algorithms and displays presentedherein are not inherently related to any particular computer or otherapparatus or with reference to any particular programming language.

Those of skill in the art will further appreciate that the variousillustrative logical blocks, modules, circuits, and algorithms describedin connection with the embodiments disclosed herein may be implementedas electronic hardware, instructions stored in memory or in anothercomputer-readable medium and executed by a processor or other processingdevice, or combinations of both. The components of the distributedantenna systems described herein may be employed in any circuit,hardware component, integrated circuit (IC), or IC chip, as examples.Memory disclosed herein may be any type and size of memory and may beconfigured to store any type of information desired. To clearlyillustrate this interchangeability, various illustrative components,blocks, modules, circuits, and steps have been described above generallyin terms of their functionality.

The various illustrative logical blocks, modules, and circuits describedin connection with the embodiments disclosed herein may be implementedor performed with a processor, a Digital Signal Processor (DSP), anApplication Specific Integrated Circuit (ASIC), a Field ProgrammableGate Array (FPGA), or other programmable logic device, a discrete gateor transistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described herein. Furthermore,a controller may be a processor. A processor may be a microprocessor,but in the alternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices (e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration).

The embodiments disclosed herein may be embodied in hardware and ininstructions that are stored in hardware, and may reside, for example,in RAM, flash memory, ROM, Electrically Programmable ROM (EPROM),Electrically Erasable Programmable ROM (EEPROM), registers, a hard disk,a removable disk, a CD-ROM, or any other form of computer-readablemedium known in the art. An exemplary storage medium is coupled to theprocessor such that the processor can read information from, and writeinformation to, the storage medium. Or, the storage medium may beintegral to the processor. The processor and the storage medium mayreside in an ASIC residing in a remote station, or as discretecomponents in a remote station, base station, or server.

The operational steps described in any of the embodiments herein aredescribed to provide examples and discussion and may be performed innumerous different sequences other than the illustrated sequences.Operations described in a single operational step may actually beperformed in a number of different steps, and one or more operationalsteps may be combined. Information and signals may be represented usingany of a variety of technologies and techniques. For example, data,instructions, commands, information, signals, bits, symbols, and chips,that may be references throughout the above description, may berepresented by voltages, currents, electromagnetic waves, magneticfields, or particles, optical fields or particles, or any combinationthereof.

Further and as used herein, the terms “fiber optic cables” and/or“optical fibers” include all types of single mode and multi-mode lightwaveguides, including one or more optical fibers that may be upcoated,colored, buffered, ribbonized, and/or have other organizing orprotective structure in a cable such as one or more tubes, strengthmembers, jackets, or the like. The optical fibers disclosed herein canbe single mode or multi-mode fibers.

Other configurations are possible to provide simultaneous analog anddigital services in an optical fiber-based DAS. For example, while someexemplary embodiments above focus on combining uplink and downlinksignals using the modulator/demodulator unit 54, FDM may also be used.Combining frequency up conversions or down conversions may be employedwhen providing FDM if RF communication signals have frequencies tooclose to the frequencies of the digital data signals to avoidinterference. While digital baseband transmission of a baseband digitaldata signal below the spectrum of the RF communication signals can beconsidered, intermodulation distortion on the RF communication signalsmay be generated. Another approach is to up convert the digital datasignals above the frequencies of the RF communication signals and alsouse, for example, a constant envelope modulation format for digital datasignal modulation. Frequency Shift Keying (FSK) and Minimum Shift Keying(MSK) modulation are suitable examples for such modulation formats.Further, in the case of FDM for digital data services, higher-levelmodulation formats can be considered to transmit high data rates (e.g.,one (1) Gb, or ten (10) Gb) over the same optical fiber as the RFcommunication signals. Multiple solutions using single-carrier (withe.g., 8-F SK or 16-QAM as examples) or multi-carrier (OFDM) areconceivable.

Many modifications and other embodiments of the embodiments set forthherein will come to mind to one skilled in the art to which theembodiments pertain, and having the benefit of the teachings presentedin the forgoing descriptions and the associated drawings.

Therefore, the description and claims are not to be limited to thespecific embodiments disclosed, and that modifications and otherembodiments are intended to be included within the scope of the appendedclaims. It is intended that the embodiments cover the modifications andvariations of the embodiments provided they come within the scope of theappended claims and their equivalents. Specific terms are used herein ina descriptive sense only and not for purposes of limitation.

We claim:
 1. A multiplex switch unit for a distributed antenna system (DAS), comprising: a plurality of head-end side inputs configured to receive a plurality of component downlink signals comprising at least one downlink radio frequency (RF) communication signal and at least one downlink digital data (DD) signal; a plurality of remote side optical outputs each configured to transmit at least one optical downlink signal; a switch connected between the plurality of head-end side inputs and the plurality of remote side optical outputs, configured to: assign each component downlink signal received from the plurality of head-end side inputs to at least one remote side optical output, including assigning at least one downlink RF communication signal and at least one downlink DD signal to a common remote side optical output; and for each remote side optical output: multiplex the respective assigned component downlink signals into a combined downlink optical signal; and transmit the respective combined downlink optical signal to the respective assigned at least one remote side optical output; a plurality of remote side optical inputs each configured to receive at least one optical uplink signal, each optical uplink signal comprising at least one component optical uplink signal, wherein: at least one optical uplink signal is a combined optical uplink signal comprising a first plurality of component optical uplink signals; and at least one combined optical uplink signal comprises at least one uplink RF communication signal and at least one uplink DD signal; and a plurality of head-end side outputs configured to transmit a second plurality of component uplink signals comprising at least one uplink RF communication signal and at least one uplink DD signal, wherein the switch is connected between the plurality of remote side optical inputs and the plurality of head-end side outputs, and is further configured to: separate each combined optical uplink signal into each of the respective component optical uplink signals; assign each component optical uplink signal to at least one remote side optical port, including assigning at least one downlink RF communication signal and at least one downlink DD signal to at least one remote side optical port; and transmit each respective component optical uplink signal toward a respective at least one head-end side output.
 2. The multiplex switch unit of claim 1, wherein the plurality of component downlink signals are electrical signals, and the switch further comprises at least one electro-optical converter configured to convert each component downlink signal into a respective component downlink optical signal.
 3. The multiplex switch unit of claim 1, wherein each combined downlink optical signal is a wave division multiplexed optical signal.
 4. The multiplex switch unit of claim 3, wherein each combined downlink optical signal is generated by a wave division multiplexer (WDM) associated with the switch.
 5. The multiplex switch unit of claim 1, wherein at least one of the plurality of head-end side inputs is further configured to connect to a service matrix unit configured to transmit at least one downlink RF communication signal and at least one downlink DD signal to the at least one head-end side input.
 6. The multiplex switch unit of claim 1, wherein the plurality of head-end side outputs are electrical outputs, and the switch further comprises at least one electro-optical converter configured to convert each component uplink optical signal into a respective component electrical uplink signal and transmit each respective component electrical uplink signal to the respective at least one head-end side output.
 7. The multiplex switch unit of claim 1, wherein each combined optical uplink signal is a wave division multiplexed optical signal.
 8. The multiplex switch unit of claim 7, wherein each combined optical uplink signal is divided by a wave division divider (WDD) associated with the switch.
 9. The multiplex switch unit of claim 1, wherein at least some of the plurality of head-end side outputs are further configured to connect to at least one service matrix unit, each service matrix unit configured to receive at least one uplink RF communication signal and at least one uplink DD signal from at least one respective head-end side output. 